RADON RISK MAPPING - A METHOD OF PREDICTING PROBLEM AREAS ON GEOLOGICAL GROUNDS

The Swedish stipulations of a maximum radon daughter level of 200 Bq.m (-3) for permanently inhabited buildings, and of 70 Bq.m(-3) for build ings built later than 1981, has created a need to evaluate the radon r isk caused by the ground. Radon risk mapping is done both on a regiona l scale and a detailed scale. When mapping, the ground is classified i nto high, normal and low risk areas. The classification work is starte d by an interpretation of all available geological material from the i nvestigated area. This is followed by field investigations including r adon measurements in possible risk areas, and control of radium conten t by gamma spectrometry in the typical rock types and soil types of th e area. Results from MRM Konsult's radon measurements show a very larg e increase of high radon houses within high risk areas, classified acc ording to the above model, if compared to randomly distributed measure ments.